Conventionally, a crane that hoists and carries a load has been known (see PTL 1). The crane includes a swivel apparatus that mainly includes a hydraulic motor. A boom is freely swivelable with respect to a traveling body.
A technique has been proposed that independently controls the flow rate of hydraulic fluid to be delivered to a hydraulic device (also called “meter in-flow rate”) and the flow rate of hydraulic fluid returned from the hydraulic device, and facilitates achievement of stability and responsiveness in a compatible manner (see PTL 2). Unfortunately, a possible case of a configuration allowing a single operation tool (lever or the like) to adjust the meter in-flow rate and the meter out-flow rate uniquely defines maneuvering characteristics accordingly. Consequently, even if such a technique is applied to the swivel apparatus, it is believed to be difficult to achieve fine maneuvering characteristics.
On the contrary, in a possible case of a configuration that includes two operation tools and allows the first operation tool to adjust the meter in-flow rate while allowing the second operation tool to adjust the meter out-flow rate, it is believed that fine maneuvering characteristics can be achieved. This is because reduction in meter out-flow rate can apply a braking force to the swivel operation due to inertia, and the swivel operation can be performed with an appropriate braking force being applied. However, such a maneuvering form must be more complicated than the conventional maneuvering form that performs the swivel operation through a single operation tool. Accordingly, a crane has been needed that can select one maneuvering form from among maneuvering forms including the conventional maneuvering form, and is capable of achieving fine maneuvering characteristics for other maneuvering forms except the conventional maneuvering form.